I asked some questions earlier this year about how the UREI 813 elements and their time aligned crossovers would fit in the Imperials and I got an answer from the master himself that it would fit. I have now tonight connected the first speaker of the pair to my HIFI and it is amazing... I built a pair of speakers two years ago based on a Swedish bass reflex patent that was adjusted to match the Altec Lansing 604 8K. They sound very good but now with the Imperial standing beside them they are not only midgets in size but also in sound reproduction. However there is some flaws in the design that I bought and downloaded. The braces A should be at least 130 cm to be flush to the bottom reflecting plate and you should also be careful with the gap from the compression chamber. Minor issues but anyway the sound is amazing. Through my years I have owned a variety of speakers ranging from Magneplanar Tympani and downwards but the old Altec Lansing 604 8G koaxial with the Eminence 15" bass speaker from the old UREI 813 takes the price.

I have now the second Imperial up and running. Unfortunately was one of the 604 8G and one of the Eminence 15" bass speaker damaged at Johannesburg intl ground handling. I managed to repair the 604 8G but not the bass speaker. Instead I bought a pair of P-Audio C15 500LF 500 Watt bass speakers. They have a FS of 39Hz, VAS 155 liters, QTS 0.29.The other Eminence is ok but they are not designed for this speaker. I have tested the speakers both with Altec Lansing 604 8K and the UREI modified 604 8G and they work perfect. Together with the new bass speakers they are amazing. I have had several friends visiting wishing that they were not married due to the size of the speakers.

The speakers have now been updated. Due to 7dB difference to HF reproduction between the Altec Lansing 604 8G coaxial`s they unfortunately must be recharged. Present setup is 2 PA Audio C15-500LF. 2 PA Audio C15-300MB and 2 JBL 2412h compression drivers connected to 2 PA Audio PH-3220 horns. To drive the speakers I am now using a Rotel RC-06 preamp driving a dbx Driverack 260 active crossover and a Rotel RMB 1077 digital 7 channel 100 W amplifier. It sounds very good and the addition of the C15-300MB has further improved the lower frequencies. I am cutting at 204 Hz and 1500Hz with a 12 dB slope. I still miss the HF characteristics from the 604 8G and I will try to find a pair of old Altec drivers. It is now becoming somewhat costly but It is fun and the addition of the active crossover makes modifications so much easier.

I am presently living in South Africa and visited Sweden last week and found a set of Altec Lansing 811B horns and 908 8B drivers. They sound much better than the JBL 2412H drivers. I have finally sent the Imperials to the paint shop and will publish a picture when they are done. I also found a pair of Mantaray MR94 horns with Altec 288 8G drivers in mint condition. They are huge and they have to wait in Sweden until I move back. It now seems that journey of building and equipping the Imperials pretty much has come to an end.

Are you are still tri-amping with a C15-500LF set at 204 hz low pass 12 db/octave, A C15-300MB thru a band pass from 204 - 1500 hz 12 db/octave, and an Altec 908 driver / 811 horn set at 1500 hz high pass 12 db/octave?

My Imperials are now in Sweden. The 811B horns are now replaced with MR 94 horns with Altec 288 8G drivers. The speakers are now 2.4 metres high with the huge horns on top. I am dividing the top at 794hz and the speakers has transformed into a higher level of HIFI. The 288 8G drivers are using a 2" diaphragm and are slower than the 1" used in the 908 but the MR 94 gives more body and voices sound natural and not edgy and compressed. The beauty with the Imperials and a DSP like the Dbx is that you can modify the sound reproduction so easy and explore new sounds and the house that I now will start to build is designed around the speakers with a living room of 70sqm. So if you are single or have an understandig wife, start to build...

I have been building my new house for 6 month now. It is nearly finished.I decided in april that if I have built a pair of modified Imperials, why not continue with a pair of bigger horns? The picture shows the final stages before they were covered. There is now a 6.1 meter long and 0.6 meter horn mouth in the living room floor. I am using 4 pcs Eighteensound 15" 15W200 woofers. They will give 124db at 20hz. I will cut them at approx 40hz. The imperials will do the rest. I will come back with a report when everything is up and running. I have been involved in modifications of a new 8 channel DSP cross over. The end result turned out to be very good. I will now start distributing them.